# matrix multiplication using co and fine-grained concurrency
# usage:  a.out dimension

resource matrix_mult()
  # read command line argument
  var n: int; getarg(1,n)
  # declare and initialize shared arrays
  var a[n,n] := ([n] ([n] 1.0)),
      b[n,n] := ([n] ([n] 1.0)),
      c[n,n] : real

  # compute inner product of a[i,*] * b[*,j]
  procedure inner(i,j: int)
    var sum := 0.0
    fa k := 1 to n -> sum +:= a[i,k]*b[k,j] af
    c[i,j] := sum
  end

  # compute n**2 inner products concurrently
  co (i := 1 to n, j := 1 to n) inner(i,j) oc

  # print result, by rows
  fa i := 1 to n ->
    fa j := 1 to n -> writes(c[i,j], " ") af
    write()
  af
end